Since you're a new user to the forum your posts take a little while to show, this will be lifted after a few days/posts.
Just played your game and it's cute. It does need a bit of work though.
First, definitely get a bitmap font to use instead of the default font for text. It just looks bad. You can find lots of free fonts on the web and convert them with Bitmap Font Creator (do a search via google ot this site it's very handy).
Next, I ran out of time on one level and it just says "opps try again" it was at first confusing because I hadn't realized I was being timed or that time ran out. You might want an audio or visual indication that time is running out and when it does, tell the player it ran out, not just "oops".
When you finish a level the sprite for the character stays on the screen one tile away from the exit. It stays there until the next level is loaded and starts. It is just weird.
"Start game with last level" - this doesn't make any sense on the first run. Also you might want to consider having the background of the message also behind the buttons and center the whole dialogue on the screen.
The Save and exit button is a little odd. You should be automatically saving. Also you could eliminate this button by just having back key functionality bring up a menu (quit or restart). Then you have a lot more room on the right for the controls which isn't really needed, but you could at least center them in the right hand side of the screen nicely.
Also you might want to consider moving all of the informational text over to the right side. Maybe have some on top and some on bottom (level / hiscore). And consider using icons instead of so much text, for lives show the character with x3 by it, gold with the gold bar by it, etc.
The control buttons have visible jagged edges. You might want to update the resolution of the button images. Higher is usually better. Most devices have at least 1000 pixels in height and they are about 15% of the screen width, so a button image that is 256x256 would look nice and smooth.
The level area itself could be a bit bigger if you eliminated the outside wall/tile or made it much thinner. The interest of a game is in the level, characters, and items. If you can make it bigger you should try.
If I move out of the game and then come back in the timer is less than 0 and it seems I can play for infinity
You might want to look at the GetResumed() command to adjust the timer. Either that or only add increments to the timer with every sync() call. I often do this:
time# = timer()
display_time = 0
do
if timer() - time# > 1.0
inc display_time
endif
sync()
loop
This way the time in the game only updates when the app is in the foreground. This doesn't work on windows as well because in Windows even when the app is not in the foreground the sync calls still happen... draws get messed up, but sync still runs...
The tiles for the stone might be more interesting if they were bricks. Also the black background is a bit boring. Animated tiles might look really cool and add a lot of visual interest.
Have you thought about the character leaving a slime trail instead of the walls closing in? That might be a bit more interesting too.
I'd also suggest animating the character, maybe with a mouth movement so it looks like he is chomping the gold. And animating the gold so it has a little sparkle to it. That would add a lot of interest, maybe the door opening too. That would give you the opportunity for some more sound effects (door opening).
There's also some opportunities for power ups here. One that would allow you to break walls for a certain amount of time immediately comes to mind. This would give the player a chance to fix their mistakes.
Well that's about all I can think of. Keep up the good work and good luck!